Though parents may want to protect their newborn from the outside world, the latest study suggests a lack of contact with certain bacteria could increase asthma risks.
The study, conducted by researchers at the University of British Columbia (UBC) and the BC Children's Hospital in Canada, is published in the journal Science Translational Medicine.
Since the 1950s, rates of asthma have increased significantly, affecting nearly 20% of children in Western countries. According to the Centers for Disease Control and Prevention (CDC), 6.8 million children in the US currently have asthma.
Characterized by inflamed air passages, the condition temporarily narrows the airways that move air from the nose and mouth to the lungs. A child who has asthma is extra sensitive to certain triggers, including viral infections, allergies and irritating particles in the air.
To further investigate why asthma rates have risen so dramatically, the researchers - led by Prof. B. Brett Finlay - examined fecal samples from 319 children who were part of the Canadian Healthy Infant Longitudinal Development (CHILD) Study.
Results showed that 3-month-old infants who were at an increased risk for asthma had lower levels of four types of gut bacteria, findings that could be used to develop a test for predicting asthma risk in children.
Babies typically obtain the four bacteria - Faecalibacterium, Lachnospira, Veillonella, Rothia (FLVR) - from their environments, but due to various factors, some do not.
First study to link gut bacteria and asthma development in humans
According to Prof. Finlay, the study "supports the hygiene hypothesis that we're making our environment too clean. It shows that gut bacteria play a role in asthma, but it is early in life when the baby's immune system is being established."
Fast facts about childhood asthma
- In the US, 9.3% of children currently have asthma
- Asthma is the leading reason for missed school days
- In children, the condition is the third-ranking cause of hospitalization.
In the human body, there are trillions of bacteria that play a vital role in our health. The so-called hygiene hypothesis proposes that changes in our lifestyle over time - to a more "hygienic" way of living - have resulted in decreased exposure to microbes that are important for our immune system.
When the team studied 1-year-old children, they also found fewer FLVR levels, suggesting the first 3 months of life are pivotal for immunity.
The findings were confirmed in mice, and the team found that newborn mice injected with the FLVR bacteria developed less severe asthma. The next step will be to develop probiotic treatments for infants to help prevent the condition.
"This discovery gives us new potential ways to prevent this disease that is life-threatening for many children," says co-lead researcher Dr. Stuart Turvey, from BC Children's Hospital. "It shows there's a short, maybe 100-day window for giving babies therapeutic interventions to protect against asthma."
The researchers further explain their findings in the video below:
Although changes in the gut microbiota have been linked to asthma development in animal models, this is the first study to suggest that these findings apply to humans. The team hopes to conduct a further study with a larger number of children to confirm their findings and explore how these bacteria affect asthma development.
Medical News Today recently reported that asthma could be inherited from grandmothers who smoke.